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Post Time: 01/12/2008 12:09:58 |
neuroki
Total Forum Posts: 13 |
Just a silly question really. I'm a bit confused re: how mobile phones work as quite often they are referred to as operating via microwaves, whereas other places refer to mobile phones working via (UHF)ultra high frequency - which is not quite the same thing.. as I understand it (which is not very well!). Can someone clarify please?
Also what's happend to the new meter for measuring radiation which was supposed to have been avialable in 2008? |
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Post Time: 02/12/2008 17:22:33 |
alasdairP
Total Forum Posts: 173 |
It isn't a silly question at all and it is rather confusing. The official IEEE and ITU (International Telecomms Union) bands do not include "microwaves" as such. There is a comparison at: www.radioing.com/eengineer/bands.html (cut and paste this link into your browser).
UHF is officially 300 MHz to 3000 MHz (3 GHz) in most of the world. "microwave" is also generally understood to be frequencies above 300 MHz (wavelengths less than one metre), but up to 300 GHz. Some mobile phone operators (especially O2 who only had GSM900 frequencies originally) issued information leaflets stating that "microwaves" were above 1000 MHz, but this has little logic other than to allow them to claim their system did not use microwaves. 1000 MHz was used as the cut point by the IEEE and the military for the end of UHF and the start of the microwave "letter" designated bands (L, S, Ku, etc). Most networks now use the GSM1800 band and all use the 2100 MHz UMTS/3G band, so they all use "microwaves" now by any definition.
The new EMFields meter has slipped in time yet again (mainly my fault). We had early working prototypes a year ago(!) but they had some minor problems. Then we though we had cracked it in August and were negotiating for a production run. Calibration was a significant cost and we have now found a way of greatly simplifying and improving this for production. This involved both hardware and software changes in the design. We now have new working prototypes that are being field tested and we are very pleased with. So, hopefully, we can go for a full production run in the New Year. The meter has two rows of 15 LEDs, one for peak signal strength in volts per metre and the other for average power in microwatts per square metre. The readings are also presented (in more detail) on a LCD alphanumeric display. I apologise for the very long delays. I have been very involved in other matters and electronic design has ended up as a background task for me over the last two years.
Alasdair
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Post Time: 02/12/2008 17:54:24 |
neuroki
Total Forum Posts: 13 |
Thanks for clarifying that. The new EMField meter sounds brilliant - volts per metre and microwatts per square metre is pretty cool! Is there anything you cannot do or do not know? :-) Keep up the fantastic work. |
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Post Time: 08/10/2009 10:42:43 |
Jean Philips
Total Forum Posts: 22 |
After an even longer than anticipated delay, the new instrument Alasdair spoke of, the Acoustimeter, is now available for hire (£35 per week) or for sale (£279 + £4 p&p)
http://emfields.org/equipment/acoustimeter.asp
Or telephone 01353 778814 Mondays to Fridays 9.00 to 1.00. |
